diff --git a/src/miner.cpp b/src/miner.cpp
index 6434ab872..42c7fc3f2 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -1161,19 +1161,30 @@ void static RandomXMiner()
                 }
 
 
-                // TODO: use same block key for groups of blocks
-                if(Mining_height > 1024 && (Mining_height % 1024 == 64)) {
-                    // At block height 1024*N+64 we should use the blockhash of block 1024*N as randomx key
-                    // use blockchain data to set a new key+input for a group of blocks
-                    uint256 randomxBlockKey;
-                    randomxBlockKey = chainActive[Mining_height - 64]->GetBlockHash();
+                // TODO: we may want to tweak these params to more closely match the 2.8 days and ~2 hrs
+                // which is what they work out to on XMR
+                // The key block will change every ~21.3 hours with a 75s block time
+                // and every ~17 hours with the default 60s block time for HSCs
+                int randomxInterval = 1024;
+                // This lag is 80 mins for 75s blocktime and 64 mins for 60s (default) blocktime for HSCs
+                int randomxBlockLag = 64;
+
+                // Use the initial key at the start of the chain
+                if( (Mining_height-randomxBlockLag) < randomxInterval) {
+                    LogPrintf("RandomX using initial key\n");
+                    randomx_init_cache(randomxCache, &randomxKey, sizeof randomxKey);
+                } else {
+                    // At heights between intervals, we use the same block key and wait randomxBlockLag blocks until changing
+                    int keyHeight = ((Mining_height - randomxBlockLag) / randomxInterval) * randomxInterval;
+                    LogPrintf("RandomX key height=%d\n", keyHeight);
+                    uint256 randomxBlockKey = chainActive[keyHeight]->GetBlockHash();
                     crypto_generichash_blake2b_state new_state;
-                    crypto_generichash_blake2b_update(&state, (unsigned char*)&randomxBlockKey, 32);
+                    crypto_generichash_blake2b_update(&state, (unsigned char *)&randomxBlockKey, 32);
                     crypto_generichash_blake2b_final(&state, randomxInput, 32);
+
+                    randomx_init_cache(randomxCache, &randomxBlockKey, sizeof randomxKey);
                 }
 
-                // TODO: use correct variables
-                randomx_init_cache(randomxCache, &randomxKey, sizeof randomxKey);
                 randomx_vm *myVM = randomx_create_vm(flags, randomxCache, NULL);
                 if(myVM == NULL) {
                     LogPrintf("Cannot create RandomX VM, aborting!\n");